Videos captured by an imaging apparatus such as a monitoring camera not only are significantly useful for prevention of crime or a criminal investigation but also can be used for a variety of applications such as exploitation in a field of marketing using an analysis of customer's traffic line or the like. However, when using a video, it is desirable to perform protection of private information or a portrait right by abstracting a person appeared in the video.
On the other hand, in order to analyze a behavior of a person appeared on a video for marketing or the like, it is desirable also to understand what action a person does or how a person interacts with a background object.
In order to meet both of these needs, it is demanded that a concrete action of a person is known and simultaneously what is on the background is seen while who a person appeared on a video is cannot be identified.
In order to meet at least some of such a demand, Patent Literature 1 discloses a technique in which a face is detected and a portion thereof is pixelated. Patent Literature 2 discloses a technique in which a portion different from a background is pixelated or painted in black. Patent Literature 3 discloses a technique of a blurring process as a means for protecting private information. Patent Literature 4 discloses a technique in which a foreground image in an image is synthesized into a background image or a mask processing or the like is performed on the foreground image depending on the authority of a user for the foreground image. Patent Literature 5 discloses a technique in which a person area is specified from an image and the person area is changed to another image. Further, Non Patent Literature 1 discloses a technique such as see-through expression or expression of a contour in a specific color.